Actually in my case also i have used =Match(QVUser(),'USER1','USER2') but my client asked that he will be create one table where all user's Domain,ID and Right will be available.Now i have to access that table and have to match OSUSER with the user having ADMIN rights for provding access to some sheets in the application.

Wow, Rob, never knew you could do that! Wish I had, could've saved me tons of time, heh! I'm sure that will prove very useful in the future! Top tip! For those who don't know: Ctrl + shift + s will overrule any conditional display of sheets or sheet objects so that everything becomes visible, and then toggles it back on again. This is especially useful for me, as I have a lot of hidden objects based on a users visibility restrictions, so working out all the permutations that can show a certain object is sometimes hard, being able to see everything no matter what is a Godsend!